Debugging ~6 min · ~24 min remaining

Five false equilibria

Identify partial sums, incorrect sets, and selections that hide reactions.

Bug hunting — Five false balances

Open 06_bug_hunt.mac and diagnose each case:

Spread selection: An attempt is made to solve without recovering the entire model.
Missing set: reactions are queried without activating a result set.
Wrong sign: reaction and charge are compared as if they had the same meaning.
global FSUM: a sum close to zero is interpreted as absence of reaction.
Non-existent moment: wanted RF,MZ in nodes without rotation and the force torque is ignored.

Don't fix the code first. For each error write: symptom, physical cause, state of MAPDL involved and minimal test that would confirm the diagnosis.

Professional incident

SOLVE succeeds, but force or moment does not close.

Incident file

This is not your session template — it is a broken script for diagnosis practice.

Evidence to retain

Initial hypothesis Changed line or block Output proving the cause Reusable prevention rule

What evidence separates the root cause from a lucky edit?

Your reflection stays in this browser.

Graduated hints

1 · Concept hint

Find the first broken contract.

2 · Command hint

Inspect state related to PRRSOL and FSUM.

3 · Explained solution

Compare with the module deliverable and explain why the corrected state restores the contract.

After running the script, reviewing the .out, and saving evidence, answer:

Quick check

FSUM runs with an accidental partial selection. What is the risk?

Summing only some reactions and reaching the wrong conclusion. Automatically changing the mesh.